On Tue, 29 Jul 2003, Leopold Toetsch wrote: > Simon Glover <[EMAIL PROTECTED]> wrote: > > Try and explain what invoke is supposed to do. NB this still needs work > > [ snip ] > > > +=item void* invoke(INTERP, PMC* self, void* next) > > [ snap ] > > > +It should set up the environment for the sub, and should return the > > +location at which operation flow should continue after the subroutine > > +returns. > > The C<invoke> vtable method gets a bytecode address, that is the > NEXT() in the opcode stream. But it returns the address, where it wants > to jump to. Returning to the passed address is not up to the called > subroutine object, setting up specific environment depends on the > called subroutine object. A look at docs/pmc/subs.pod might provide some > hints. > > So the invoke opcode branches to the address it got from the invoke > vtable, normally: eval.pmc is slightly different or it takes just longer > to branch really there ;-) > > Sorry if that was missleading in my first answer regarding that topic.
I said the current draft needed work :-) > Anyway, there are no really general rules what the vtables do. They are > some kind of overloading (e.g. get_integer()): > > set I0, P0 # get an integer from a scalar > set I1, P1 # get size of aggregate P1 Yes, but in both cases we can still document the general intent of the method: it returns an integer value from the specified PMC. Now, what that value _actually represents_ is another matter, and you're right that PDD02 isn't the place to discuss that. I shall try and add something along these lines to the docs soon, but I don't have time tonight. Simon
